javascript - How can a JS tree node retain a reference to its parent without becoming circular? -

i'd have tree structure each node can have reference parent node, so:

class tree {   constructor(name, parent = null) {     this.name = name;     this.children = [];     this.parent = parent;   }    appendchild(name) {     this.children.push(new tree(name, this));   } }  let mytree = new tree("sarah"); mytree.appendchild("laura"); 

the problem such structure impossible represent in json, because it's circular: sarah contains reference child laura contains reference parent sarah contains reference child laura, , on.

what i'd child have pointer parent, doesn't evaluated full parent. don't think that's possible. should do?

add custom tojson method, resolves references strings id, add fromjson method opposite, e.g:

tree.tojson=function(tree,i=0){   tree.lookup=i;   tree.children.foreach(function(child){     child.parent=i;     tree.tojson(child,++this.i);   },{i});   if(!i) return json.stringify(tree); }  tree.fromjson=function(tree,lookup=new map()){   if(typeof tree==="string")  tree=json.parse(tree);   lookup.set(tree.lookup,tree);   tree.children.foreach(function(child){     child.parent=lookup.get(child.parent);     tree.fromjson(child,lookup);   });   return tree; } 

but if talking parent reference, might easier simple remove it, , add later:

//tojson tree.children.foreach(function(child){   delete child.parent; });  //fromjson tree.children.foreach(function(child){  child.parent=tree; });